This proposal prepared by the department of Chemistry of Harvard University is intended to secure funds for the acquisition of a 500 MHz high resolution fourier transform nuclear magnetic resonance (NMR) spectrometer, specifically for 2-D applications. This new instrument will enable research workers in the department to better understand the structures and interactions of complex organic, inorganic, an biologically important molecules. The user group includes synthetic organic and bioorganic chemists and biophysical chemists. REsearch conducted by this group includes synthesis of biologically active substances (prostaglandins, leukotrienes, thromboxanes, blood group substances, immunostimulators, antibiotics, proteins, sugars, hormones, nucleic acids), structural determination of natural products and synthetic intermediates, examination of biological pathways and intermediates and virus-receptor interactions.